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• Get image from direct show device [duplicate]

  13 août 2014, par user2663781

  This question already has an answer here :

  • Capturing image from webcam in java ?
    
    15 answers
    

  I want to get image from direct show device in Java but I can’t find a good solution for it.
  My device is screen-capture-recorder which is easy to get with ffmpeg, so my first idea was to use Xuggler.
  I tried this code :

  String driverName = "dshow";
  
  String deviceName= "screen-capture-recorder";
  
  // Let's make sure that we can actually convert video pixel formats.
  
  if (!IVideoResampler.isSupported(IVideoResampler.Feature.FEATURE_COLORSPACECONVERSION))
  
            throw new RuntimeException("you must install the GPL version of Xuggler (with IVideoResampler support) for this demo to work");
  
  // Create a Xuggler container object
  
  IContainer container = IContainer.make();
  
  // Tell Xuggler about the device format
  
  IContainerFormat format = IContainerFormat.make();
  
  if (format.setInputFormat(driverName) < 0)
  
            throw new IllegalArgumentException("couldn't open webcam device: " + driverName);
  
  // devices, unlike most files, need to have parameters set in order
  
  // for Xuggler to know how to configure them, for a webcam, these
  
  // parameters make sense
  
  IMetaData params = IMetaData.make();
  
  params.setValue("framerate", "30/1");
  
  params.setValue("video_size", "320x240");
  
  
  
  // Open up the container
  
  int retval = container.open(deviceName, IContainer.Type.READ, format,
  
  false, true, params, null);

  But when I try to open the device (by his device name) it is not working :
  0 [main] ERROR org.ffmpeg - [dshow @ 05168820] Malformed dshow input string.
  0 [main] DEBUG com.xuggle.xuggler - Could not open output url : screen-capture-recorder (../../../../../../../csrc/com/xuggle/xuggler/Container.cpp:436)
  Exception in thread "main" java.lang.IllegalArgumentException : could not open file : screen-capture-recorder ; Error : Input/output error
  at DisplayWebcamVideo.main(DisplayWebcamVideo.java:99)
  Java Result : 1

  After searching a bit I found DSJ, but it is for non-commercial use only and we need a registry version, so impossible to use for me.

  I also found LTI-CIVIL but it could not detect the "screen-capture-recorder".
  I tried FMJ and JMF but it does not find the device too.

  I tried VLCj but the container with the video must be open if I want to get image and it is not what I need.

  I tried webcam-recorder (github.sarxos.webcam), it detects the device but i got this error when I try to open it :

  #
  
  # A fatal error has been detected by the Java Runtime Environment:
  
  #
  
  #  EXCEPTION_ACCESS_VIOLATION (0xc0000005) at pc=0x5faf910d, pid=2552, tid=9780
  
  #

  I am a bit stuck now, I don’t know how to solve this problem someone can help me ?
  Or give me a simple DLL that I can use through JNA to get an image from direct show device...

• How to show segment lengths of hls file with ffmpeg

  30 mai 2017, par endorphins

  I’m trying to use ffmpeg to retrieve the segment duration of every segment for every stream of an HLS file. It looks like I can do this if I know all of the names of the individual files in advance and call ffprobe on each one. This seems really tedious and I won’t always know the names of all of the individual files, only the main .m3u8. Is there any way I can get all of this information with just one ffmpeg command ?

  Additionally, is the duration retrieved by ffprobe on a .aac file accurate ? I get the message that it’s "Estimating duration from bitrate, this may be inaccurate".

• How to show video (no audio) from ffmpeg via RTP in VLC ?

  15 juillet 2019, par Sagi Mann

  I’m trying to stream RTP (video only) from ffmpeg to VLC :

  ffmpeg -stream_loop -1 -i video.mp4 -vcodec copy -an -f rtp rtp://0.0.0.0:1235

  In VLC app, I do file -> "open network" and set the url to rtp ://@:1235.
  But I get an error :

  SDP required
  
  A description in SDP format is required to receive the RTP stream.
  
  Note that rtp:// URIs cannot work with dynamic RTP payload format (96).

  What am I doing wrong ? I see in ffmpeg’s output that SDP is being generated :

  SDP:
  
  v=0
  
  o=- 0 0 IN IP4 127.0.0.1
  
  s=No Name
  
  c=IN IP4 0.0.0.0
  
  t=0 0
  
  a=tool:libavformat 58.20.100
  
  m=video 1235 RTP/AVP 96
  
  b=AS:1205
  
  a=rtpmap:96 H264/90000
  
  a=fmtp:96 packetization-mode=1; sprop-parameter-sets=Z01AH9oBQBbsBEAAAAMAQAAADIPGDKg=,aO88gA==; profile-level-id=4D401F